It is well known to generate or design a document using a computer-based text editing or graphics package. Once generated, a document can be printed. Typically, the package or a print driver formats the document into a printer file that can be received and interpreted by a printer.
This principle typically applies to all types of printers, for example laser printers, ink jet printers, impact printers and thermal printers, and in general to other hardcopy devices such as plotters or facsimile machines. Conveniently, herein, the term “printer” covers all such different types of printers, or other hardcopy or document rendering apparatus and devices.
Also, for the sake of convenience of description herein, the term “document” will hereafter be used to denote a document in any state, including (but not limited to) when viewed on a computer display, when formatted as a printer file ready for printing, and when in hardcopy form. The state the document is in at any point in the description may depend on the context. Also, a “document” may include text, graphics or mixed representations.
Distributed computer systems make it possible for a single ‘network’ printer to be used by multiple users. Typically, network printers are attached to computing platforms operating as print servers within distributed systems. Alternatively, some printers, given appropriate interfaces, can be arranged to connect directly to the network of a distributed system.
Documents may, however, contain sensitive information. Remote printing of sensitive documents may therefore provide a malicious party with the ability to access such sensitive information.